1. Field of the Invention
The present invention relates to a display device including a display element having a pair of electrodes.
2. Description of the Related Art
There is known a display device that has a pair of electrodes and displays images by application of voltage between the electrodes.
In a liquid crystal display device, a liquid crystal is sandwiched between a pair of electrodes in a pixel, light from a backlight provided on a rear side transmits the liquid crystal, and the amount of transmitted light is controlled by the liquid crystal that polarizes light, whereby an image is displayed. There are a passive-matrix liquid crystal display device and an active-matrix liquid crystal display device including thin film transistors (TFTs).
In addition, organic EL (electroluminescent) elements have been actively researched and developed. In the fundamental structure of an organic EL element, a layer containing a light-emitting organic compound is sandwiched between a pair of electrodes. By voltage application to this element, the light-emitting organic compound can emit light.
Like a liquid crystal display device, a display device including an organic EL element has a passive-matrix structure, an active-matrix structure, or the like. An organic EL element is a self-light-emitting element that can be formed in a film shape, and does not need a backlight, which is required in a liquid crystal display device; therefore, a thin and lightweight display device with high contrast can be achieved. For example, Patent Document 1 discloses an example of a display device including an organic EL element.
[Reference]
Patent Document 1: Japanese Published Patent Application No. 2002-324673